Syntheses of natural products from semi-mangrove plants

Nature is commonly accepted to be on of the most important resource for new active agents and medicinal products. With an increased understanding of biological processes, research including the search for new target structures has focused on oligosaccharides and glycoconjugates.[1] Their high functionalisation and complexity have challenged and will challenge synthetic chemists. One simple example is the successful isolation and structure elucidation of sophorose containing glucosides 1+2 from semi-mangrove plants of the genus Acanthus, which are used as an anti-inflammatory and antihepatitis agent in traditional Chinese medicine. [2-4]

The current work focuses on the synthesis of natural products Zizybeoside I (1) from A. ebracteatus and phenylethyl-O-beta-D-glucopyranosyl-(1,2)-beta-D-glucopyranoside (2) from A. ilicifolius. To avoid a long synthesis of the expensive sophorose glycon in this work the synthesis starts from fermented sophorose-lipids.

[1] Z. Xiangming, R. S. Richard, Angew. Chem. Int. Ed. 2009, 48, 1900-1934; 'New Principles for Glycoside-Bond Formation'.
[2] Min-Yi Li, Qiang Xiao, Jian-Yu Pan, Jun Wu, Nat. Prod. Rep. 2009, 26, 281-298; 'Natural products from semi-mangrove flora: source, chemistry and bioactivities'.
[3] J. Wu, S. Zhang, Q. Xiao, Q. Li, J. Huang, L. Long, L. Huang, Phytochemistry 2003, 63, 491-495; 'Phenylethanoid and aliphatic alcohol glycosides from Acanthus ilicifolius'.
[4] T. Kanchanapoom, R. Kasai, C. Picheansoonthon, K. Yamasaki, Phytochemistry 2001, 58, 811-817; 'Megastigmane, aliphatic alcohol and benzoxazinoid glycosides from Acanthus ebracteatus'.